Lights

I dunno, with the light set on low, you get used to the brightness and able to see the darkened area fairly well as well as the beam.

With the accelerometer, there's not much chance of getting used to a certain brightness and suddenly when you had it bright, it take a while to get used to the lower setting all over again.

You must be riding in traffic-free areas. I've never gone for more than 30min of night riding before staring down the headlights of a car.